InviteTo invite another player to your club, the player can't be a member of another club. To invite such a player you need be at the same game table, tap on the player icon and choose 'Invite' from the interaction panel. Just tap it, and the player will receive an invitation to the club, which they will need to accept.

Requests
Requests are visible if the Club Type is 'Invite Only'. The Leader and co-leader are authorized to accept or deny invitations from other Players. All requests land in the 'Requests' tab in the Club Lobby. The number of Requests is visible as well. After the first rejection, a player can send another request. If the player was rejected for the second time, they will not be able to send a request again. However, that player can still be invited to the club by a leader / co-leader.